L10-The Nervous System

Question 1

One synapse reflex arc

Answer 1

stimulus hits sensory/integrator neuron and travels to muscle or other effector to produce a response.

Question 2

Multiple synapse reflex arc

Answer 2

stimulus travels through sensor neuron, to intergator neuron, to muscle or effector and causes a response

Question 3

define cephalization

Answer 3

the concentration of neurons in the head

Question 4

T/F: integrator neuron can receive stimulus from sensor neuron and decide whether or not to pass on the response

Answer 4

true

Question 5

What does the integrator do?

Answer 5

interprets response and passes it on to effector

Question 6

3 main trends in the evolution of nervous system

Answer 6

1. integrating neurons in a CNS (reflex arcs)
2. longitudinal centralization (ie. nerve cord)
3. cephalization (concentration of neurons in head)

Question 7

What does it mean when they say, “neurons share directionality?”

Answer 7

they receive info from one end and transmit the info at the other

Question 8

significance of the glass sponge in studies about the evolution of the nervous system?

Answer 8

The glass sponge is able to generate action potentials when it gets bumped.
External stimulus causes an electrical response.
Much much slower than neurons.

Question 9

Sponges are studied to understand evolution of NS because….

Answer 9

They are on the brink of evolving a nervous system.

They contain much of the genetic coding for important NS elements.

Question 10

describe an anemone nervous system

Answer 10

“nerve net”

-diffuse web of neurons with no discernible concentration of neurons in any one place.

Question 11

Nervous systems were at first _____ and then evolved to become ________

Answer 11

Nervous systems were at first DIFFUSE and then evolved to become CENTRALIZED